Fix for Volumio str/int issue #19086

[JoakimLindbom]

Description:

Casting added to volume calculation to avoid type mismatch error.

Related issue (if applicable): fixes #19086

Pull request in home-assistant.io with documentation (if applicable): home-assistant/home-assistant.io#<home-assistant.io PR number goes here>

Checklist:

• [Y] The code change is tested and works locally.
• [Y] Local tests pass with tox. Your PR cannot be merged unless tests pass
• [Y] There is no commented out code in this PR.

If user exposed functionality or configuration variables are added/changed:

• [N] Documentation added/updated in home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• [N] New dependencies have been added to the REQUIREMENTS variable ([example][ex-requir]).
• [N] New dependencies are only imported inside functions that use them ([example][ex-import]).
• [N] New or updated dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.
• [N] New files were added to .coveragerc.

If the code does not interact with devices:

• [N] Tests have been added to verify that the new code works.

[homeassistant]

Hi @JoakimLindbom,

It seems you haven't yet signed a CLA. Please do so here.

Once you do that we will be able to review and accept this pull request.

Thanks!

[rohankapoorcom]

Nice, thanks!